METHOD FOR ACCURATE TIME-OF-FLIGHT CALCULATION ON THE COST-EFFECTIVE TOF LIDAR SYSTEM
A method for calculating time-of-flight on a LiDAR system is provided. The method comprises transmitting outgoing light pulses to a beam steering system that redirects the outgoing light pulses to a field of view of the LiDAR system; detecting return pulses corresponding to the outgoing light pulses; obtaining an intensity of a return pulse of the detected return pulses; determining whether the intensity of the return pulse is within an intensity threshold; and based on the determination, selecting a pulse-center based method or a pulse-edge based method for measuring a time-of-flight between the return pulse and the corresponding outgoing light pulse. The time-of-flight is a time lapse between a timing of the return pulse and a timing of the corresponding outgoing light pulse. The method further comprises measuring the time-of-flight based on the selected method.
1 . A light detection and ranging (LiDAR) system, comprising:
a beam steering system;
a light source configured_to emit outgoing light pulses that are steered by the beam steering system in accordance with a field of view of the LiDAR system;
a detection system configured to detect return pulses corresponding to the outgoing light pulses; and
a controller comprising one or more processors, a memory device, and processor-executable instructions stored in the memory device, the processor-executable instructions comprising instructions for:
obtaining an intensity of a return pulse of the detected return pulses,
determining whether the intensity of the return pulse is within an intensity threshold,
based on the determination, selecting a pulse-center based method or a pulse-edge based method for measuring a time-of-flight between the return pulse and the corresponding outgoing light pulse, the time-of-flight being a time lapse between a timing of the return pulse and a timing of the corresponding outgoing light pulse, and
measuring the time-of-flight based on the selected method.
2 . The LiDAR system of claim 1 , wherein selecting the pulse-center based method is based on the determination that the intensity of the return pulse is within the intensity threshold, and wherein selecting the pulse-edge based method is based on the determination that the intensity of the return pulse is not within the intensity threshold.
3 . The LiDAR system of claim 1 , wherein selecting the pulse-center based method is based on the determination that the intensity of the return pulse is not within the intensity threshold, and wherein selecting the pulse-edge based method is based on the determination that the intensity of the return pulse is within the intensity threshold.
4 . The LiDAR system of claim 1 , wherein the timing of the return pulse determined using the pulse-center based method is determined by finding a weighted mean of the return pulse.
5 . The LiDAR system of claim 1 , wherein the timing of the return pulse determined using the pulse-edge based method is determined by finding a timing of an edge of the return pulse.
6 . The LiDAR system of claim 1 , wherein the processor-executable instructions comprise further instructions for:
adjusting the measured time-of-flight using an intensity to distance correction table.
7 . The LiDAR system of claim 6 , wherein the intensity to distance correction table comprises parameters to be adjusted when the pulse-edge based method is selected.
8 . The LiDAR system of claim 1 , wherein the intensity threshold is about 8%.
9 . The LiDAR system of claim 1 , wherein the detection system comprises:
at least one receiving lens;
a detector comprising an avalanche photo diode (APD) detector; and
an analog-to-digital converter (ADC).
10 . A method for using a light detection and ranging (LiDAR) system, comprising:
transmitting outgoing light pulses to a beam steering system that redirects the outgoing light pulses to a field of view of the LiDAR system;
detecting return pulses corresponding to the outgoing light pulses;
obtaining an intensity of a return pulse of the detected return pulses;
determining whether the intensity of the return pulse is within an intensity threshold;
based on the determination, selecting a pulse-center based method or a pulse-edge based method for measuring a time-of-flight between the return pulse and the corresponding outgoing light pulse, the time-of-flight being a time lapse between a timing of the return pulse and a timing of the corresponding outgoing light pulse; and
measuring the time-of-flight based on the selected method.
11 . The method of claim 10 , wherein selecting the pulse-center based method is based on the determination that the intensity of the return pulse is within the intensity threshold, and wherein selecting the pulse-edge based method is based on the determination that the intensity of the return pulse is not within the intensity threshold.
12 . The method of claim 10 , wherein selecting the pulse-center based method is based on the determination that the intensity of the return pulse is not within the intensity threshold, and wherein selecting the pulse-edge based method is based on the determination that the intensity of the return pulse is within the intensity threshold.
13 . The method of claim 10 , wherein the timing of the return pulse determined using the pulse-center based method is determined by finding a weighted mean of the return pulse.
14 . The method of claim 10 , wherein the timing of the return pulse determined using the pulse-edge based method is determined by finding a timing of an edge of the return pulse.
15 . The method of claim 10 , further comprising:
adjusting the measured time-of-flight using an intensity to distance correction table.
16 . The method of claim 15 , wherein the intensity to distance correction table comprises parameters to be adjusted when the pulse-edge based method is selected.
17 . The method of claim 10 , wherein the intensity threshold is about 8%.